The star power under a tented ballroom enclosing a blocklong stretch of Beverly Hills' Crescent Drive was intense. Kevin Spacey, Jodie Foster, Amy Adams, Gwen Stefani, Demi Moore and 1,000 or so other influencers came out in glittering gowns and tuxes for the Oct. 17 opening gala of the Wallis Annenberg Center for the Performing Arts.

But when the time came to toast the night's most powerful person, all eyes were on a woman few have seen in person, though her name appears on several major Los Angeles buildings.

FOR THE RECORD: Saturday Calendar: A story on Wallis Annenberg indicated that Brad Pitt and Robert Redford attended the opening gala of the Wallis Annenberg Center for the Performing Arts. While they were co-hosts and co-chairs of the gala, they did not attend the gala. Also, the former mayor of Beverly Hills is Vicki Reynolds, not Beverly Reynolds. —

Wallis Annenberg, beaming in a sparkling sapphire-and-black dress, leaned into a gracious Spacey beside her as if a bit overwhelmed at the attention. Thunderous applause filled the room as photographers rushed the table she shared with Spacey, Charlize Theron, Tim Robbins, former studio chief Sherry Lansing and William Friedkin.

The billionaire benefactor's newest project at the renovated Beverly Hills Post Office, already nicknamed the Wallis, opens its doors to the public on Friday with an inaugural performance by the Martha Graham Dance Company. Without her $25-million gift, starting with $15 million given in 2004, the center never would have been built.

"Her name gave us credibility. From that time on," said former Beverly Hills Mayor Vicki Reynolds, who worked with Annenberg to turn the post office into a cultural center, "we were able to gather people around it with momentum."

Annenberg, heiress to her father Walter's Triangle Publications publishing empire (TV Guide, and Seventeen magazines), is one of Los Angeles' most active philanthropists. She may not be on the current Forbes 400 list of the wealthiest Americans, but she's chairman of the board, president and chief executive of her father's Annenberg Foundation, with assets of about $1.5 billion, according to its most recent public filing. Since her involvement in 2002, the foundation has distributed more than $750 million to about 2,000 Los Angeles organizations.

"Wallis has a great sense for what to invest in that [which] will expand and increase in importance over time," said Michael Govan, CEO and director of the Los Angeles County Museum of Art. "There's all the performing arts in downtown and the Broad Stage in Santa Monica; strategically, the idea of investing in a prominently located performing arts center in Beverly Hills was smart. There are the tourists; there's a sustainable audience. It will magnify the resonance of the performing arts in L.A. in general."

Philanthropist and entrepreneur Eli Broad is also impressed with the new center.

"The Wallis is a great addition," Broad said by telephone. "It's another jewel in the region's cultural crown."

As to why he and Annenberg seem to be the only patrons single-handedly funding the arts in Los Angeles, Broad added, "Boston, San Francisco and New York are all older cities that have a great tradition of philanthropy. Los Angeles is just now building a tradition of philanthropy. Wallis and our family have … been especially supportive of the arts in our city. Now that we have Grand Avenue with a cultural district that serves a region of 14 million residents, I expect that more people will want to follow our lead."

Since its 1989 inception, the Annenberg Foundation, under Walter, put its name on a panoply of buildings, the Annenberg School for Communications at both USC and the University of Pennsylvania, among them. After her father's 2002 death, Annenberg became the foundation's vice president; when her stepmother, Lee, died in 2009, she took over the organization.

Over 11 years, Annenberg has broadened the foundation's philanthropic philosophy from that of predominantly media, education and the arts to include animal welfare, veterans support and environmental issues. The Annenberg is in the formative stages of helping to fund the California Department of Fish and Wildlife's project of reimagining public access to the Ballona Wetlands.

Divorced since 1975 from Seth Weingarten, Annenberg, 74, has brought her children into the philanthropic fold. Three of four of them are active vice presidents and co-directors of the Annenberg Foundation. Her daughter, Lauren Bon, and her son Gregory Annenberg Weingarten are both working artists as well; her youngest, Charles Annenberg Weingarten, is a filmmaker with a masters from USC.

The Annenberg-Weingarten clan moved to Los Angeles from Roswell, N.M., where Weingarten was doing service at Walker Air Force Base; the family moved so Weingarten could take a position at UCLA. It wasn't until Annenberg took the helm of her father's foundation in 2009, however, that the organization's headquarters were relocated from Pennsylvania — where Annenberg grew up in Philadelphia's tony Main Line area — to Los Angeles.

Through a handful of ambitious public spaces, Annenberg has put her personal stamp on Los Angeles. Among them are the Wallis Annenberg building at the California Science Center, Century City's Annenberg Space for Photography and Santa Monica's Annenberg Community Beach House.

Annenberg is famously press shy. In a rare TV interview this month, she described herself as "a person who likes to sit in a very comfortable chair with a martini and watch a good football game."

She is as devoted to the fine arts as she is to football. Annenberg is the only regular board member of both LACMA and L.A.'s Museum of Contemporary Art, and she has been publicly supportive, with her voice and her wallet, of both museums. In 2012, when MOCA's former director Jeffrey Deitch came under fire after the ousting of chief curator Paul Schimmel, Annenberg wrote a letter to the Los Angeles Times in his defense:

"Deitch has a great sense of where the art world is headed," she wrote. "His talents aside, MOCA can no longer survive as an insular and elite institution. It needs to welcome everyone, and that means exhibits and events that draw people in with big ideas and, yes, provocative statements."

So large was Annenberg's 2002 grant of $10 million to endow LACMA's director's position that when Govan joined the museum in 2006, he was given the title "CEO and The Wallis Annenberg Director, LACMA."

In 2008, the Annenberg Foundation gave LACMA an additional $23 million toward its capital campaign and to help it acquire the Marjorie and Leonard Vernon Collection of more than 3,500 seminal 19th and 20th century photographs.

Govan calls it "one of the finest collections of photography in private hands in America." Not surprisingly, LACMA renamed its photo department the Wallis Annenberg Department of Photography.

The Wallis, more than a decade in the making, was designed by Studio Pali Fekete architect Zoltan Pali, who specializes in renovating historic buildings. It features two performance spaces — the smaller 125-seat Lovelace Studio in the former post office space and the brand-new, 500-seat Bram Goldsmith Theater.

Unlike some arts philanthropists, whose generous gifts often come with passionate opinions, Annenberg was fairly hands off during the development of the performing arts center, said Lou Moore, executive director of the Wallis.

"She heard our vision and knew the post office because she'd raised her children in Beverly Hills," Moore said. "The idea of preserving a landmark building meant a lot to her. The detail work, she left to the professionals."

Architect Pali said, "I only met her twice, briefly, at large fundraising events. Even though it was her namesake, she stayed completely away from it."

Nearly everyone who worked toward bringing the Wallis to life, including Reynolds, Moore and even Beverly Hills' current mayor, John. A. Mirisch, said that Annenberg, who now lives in Century City, was particularly heartfelt about the project.

"I've known Wallis Annenberg since I was a child. She has always been passionate about our city," Mirisch said. "She has given our residents, our visitors and Beverly Hills, as well as future generations, a gift which will hopefully benefit our city for at least our next 100 years."